Products including edibles colored with polymeric red colors

- Dynapol

Polymeric red colors having the structure ##STR1## wherein R.sub.1 and R.sub.2 are independently selected from among hydrogen, halos, lower alkyls, lower alkoxies, nitros, and sulfonates, R.sub.3 is selected from hydrogens, alkyls and alkylsulfonates, and R.sub.4 is an alkyl-containing polymer linking a plurality (n) of anthraquinones into a polymeric colorant are disclosed to be used as nonabsorbable colorants for edibles and cosmetics. They may also be used in such substrates as lakes.

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1. Field of the Invention

This invention relates to colorants. More particularly, it concerns a family of red colorants which per se and as lakes find special application as red colorants for edibles and cosmetics.

2. The Prior Art

FD&C Red #2, a monoazo dye of the formula ##STR2## commonly known as Amaranth, was among the most widely used colors in foods, drugs and cosmetics. In 1975 these uses were prohibited in the United States when the Food and Drug Administration ruled that the dye's safety was questionable. The removal from commerce of this compound has left a great need. Edibles such as cherry, raspberry, and strawberry-flavored gelatin desserts, beverages, candies and jams, and nonedibles such as inks and dyes were formulated around the particular tint and hue of this color. Several replacement colors have been proposed but have not been fully acceptable. For example, FD&C Red #40, another monoazo dye which has the formula ##STR3## and which is disclosed in U.S. Pat. No. 3,640,733, issued Feb. 8, 1972 to Rast et al., is now being used as a replacement. This material has a brownish cast which interferes with many uses. Natural colors, such as are extracted from beets, have been suggested as well but have low coloring power, and thus unacceptably high costs in use. The present invention seeks to provide a replacement for now-delisted azo color Red #2. This invention discloses a limited family of new anthraquinone colorants which are excellent color matches for Red #2. The colorants of this invention can take on two forms. They can be monomeric, as have been all food colors approved for use heretofore. Preferably, however, these new colors are in polymeric form. As is disclosed in U.S. Pat. No. 3,920,855, issued Nov. 18, 1975 to Dawson et al., in copending United States patent application Ser. No. 520,530, filed Nov. 4, 1975 by Gless et al., now U.S. Pat. No. Re. 30,362 and in Japanese patent applications of Tanabe, such as Nos. 41-14433, 41 -14434 and 44-13382, having colors in polymeric form can be advantageous. When polymeric colors are used in edibles, if the size of the molecules of polymeric color exceeds a certain limit--usually a molecular size of from about 1000 to 2000 Daltons--and if the color compounds do not break down and thus maintain this size, the polymeric colors are not absorbed through the walls of the gastrointestinal tract. This means that when such materials are eaten, they essentially pass directly through the gastrointestinal tract. They are not taken into the body or its systemic circulation and thus any risk of possible systemic toxicity is eliminated.


The new and useful anthraquinone colors employed in this invention have the following structural formula I. ##STR4## wherein R.sub.1 and R.sub.2 are independently selected from hydrogen, halos of atomic number 9 through 53, nitros, lower alkyls and lower alkoxies of from 1 to 3 carbon atoms, and sulfonates; R.sub.3 is selected from hydrogens, lower alkyls and alkyl sulfonates of from 1 to 4 carbon atoms, and R.sub.4 is a noncrosslinked organic polymeric backbone which covalently links together a plurality (n) of units of this color into polymeric form. These materials are used per se and as lakes to color edible substrates and cosmetics.


In the colors of Formula I, R.sub.1 and R.sub.2 independently are selected from the class of substituents consisting of hydrogen; halos selected from fluoro, bromo and iodo; nitro; lower alkoxies selected from methoxy, ethoxy or propoxy; lower alkyls selected from methyl, ethyl and propyl and sulfonate.

The remaining three positions on the pendant nonfused aromatic ring to which R.sub.1 and R.sub.2 are covalently bonded carry hydrogens. R.sub.1 and R.sub.2 preferably are separately attached to the ring at the 2, 4 or 6 positions. Preferably, R.sub.1 is hydrogen and R.sub.2 is selected from the class of substituents set forth hereinabove. More preferably, R.sub.1 is hydrogen and R.sub.2 is hydrogen, chloro or methoxy.

In a most preferred color R.sub.1 and R.sub.2 are both hydrogen. This is an excellent red. Surprisingly, the presence of the diverse range of other R.sub.1 and R.sub.2 substituents, varying from stongly electron withdrawing nitro groups to strongly electron donating alkoxy groups makes only minor differences in the shade of these colors. A group of preferred colors having a single nonhydrogen substituent on the nonfused ring is shown in Table I.

TABLE I ______________________________________ Substituent Ring Position ______________________________________ Cl 2 or 4 Br 2 or 4 SO.sub.3.sup.- M.sup.+ 4 NO.sub.2 2 or 4 --O--CH.sub.3 2 or 4 --OC.sub.2 H.sub.5 2 or 4 ______________________________________

In the colors used in this invention, R.sub.3 is selected from hydrogen, lower alkyls of from 1 to 4 carbons, i.e., methyl, ethyl, propyl or butyl, and lower alkyl sulfonates of from 1 to 4 carbon atoms, i.e., methyl sulfonate, ethyl sulfonate, propyl sulfonate and butyl sulfonate. In preferred monomeric colors, R.sub.3 is hydrogen.

The colors employed in this invention are in polymeric form. This can be represented structurally by defining R.sub.4 as a polymer linking together a plurality (n) of units of the color molecule or, and this is considered to be a better description, the polymeric colors can be represented by the following structural formula: ##STR5## wherein R.sub.1, R.sub.2 and R.sub.3 are as previously defined not only in general but also as to preferences. B is an organic polymeric backbone attached to N by a covalent bond and characterized by having essentially no crosslinks and by containing only covalent bonds which are stable under the acidic, basic, and enzymatic conditions of the mammalian gastrointestinal tract; n is a number greater than 1, preferably from 10 to 2000 and more preferably from 20 to 1000.

Preferred backbones are carbon-oxygen ether backbones and essentially linear alkyl carbon-carbon backbones containing pendant primary and lower alkyl secondary amines in acetylated or unacetylated form, with or without additional covalently attached pendant groups such as sulfonates, phosphonates, carboxyls and the like. Examples of these preferred backbones and the resulting polymeric colors are given in Table II.

TABLE II __________________________________________________________________________ Backbone Polymeric Color __________________________________________________________________________ polyvinylamine ##STR6## n = 10 to 4000, preferably 100-2000 m = 0.3 to 5n polyvinylamine with acetylated residual amines ##STR7## copoly(vinylamine/ vinylsulfonate) (shown in sodium form) (other alkaline metals will work) (amine can be 1 to 3 carbon N-alkyl amine as ##STR8## copoly(vinylamine/vinyl sulfonate) with acetylated residual ##STR9## poly N-methylvinylamine (other n-lower alkyl amines can be used as ##STR10## copoly(vinylamine/ acrylic acid) (amines can be acetylated as ##STR11## sulfonated polyvinylamine or N-methylvinylamine or the like ##STR12## R = lower alkyl of 1 to 3 carbons or hydrogen (secondary alkyl and primary amines can be acetylated) aminated poly(epichloro- hydrin) (with added sulfamates) ##STR13## aminated and acetylated poly(epichlorohydrin) ##STR14## __________________________________________________________________________ ##STR15##

Among backbones, polyvinylamine and copoly(vinylamine/vinylsulfonate), either acetylated or unacetylated, are preferred. These preferred backbones preferably have molecular weights of about 10,000 to about 150,000 Daltons and, in the case of the copolymer, an amine to sulfonate ratio of from 1:1 to 3:1. A polyvinylamine meeting this weight range has from about 200 to about 3000 units, a copolymer--from about 60 to about 1800 amine units. The choice among backbones often depends upon the degree of water solubility required of the final polymer colorant product. Polar groups such as carboxyls, phosphonates and especially sulfonates are required in the polymeric colorant to impart good water solubility properties. When the color unit itself contains sulfonates, i.e., when R.sub.1 and/or R.sub.2 are sulfonates or alkyl sulfonates, it is not necessary to have these polar groups attached to the backbone as well. When the color unit does not contain sulfonate R.sub.1 's or R.sub.2 's, good water solubilities, i.e., solubility in pH 7 room temperature water of at least 1000 ppm, are achieved only when a backbone containing polar groups--such as the copolymer backbones--is employed.

The colors employed in this invention may be prepared by the following routes. These routes are presented as exemplary methods and are not to be construed as limiting the scope of this invention.

The first route begins with 1-amino-2-methyl-4-bromoanthraquinone, a material marketed by Sandoz Color and Chemical under the tradename AMBAX, or made as in Example I. ##STR16##

This material is reacted with a benzylic acid chloride, ##STR17## corresponding to the nonfused pendant aromatic ring desired in the colorant as follows: ##STR18##

This reaction is carried out in liquid phase in a reaction solvent. Suitable solvents include aprotic organic liquids especially cyclic and acyclic olefinically saturated aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, hexane, cyclohexane, heptane, C.sub.6 -C.sub.9 hydrocarbon mixed solvents, cyclic and acyclic ethers such as dimethoxyethane. 1,4-dioxane, diglyme, and the like. This reaction is carried out at elevated temperatures such as from C. to C. with temperatures of from C. to C. being preferred. In our work the atmospheric reflux temperature of the solvent has been used. The reaction could be carried out under pressure to obtain higher temperatures if desired. Reaction time is inversely proportional to temperature. Reaction times of from a few (3-5) minutes to about 24 hours generally are employed. The following examples will aid in selecting times and temperatures. At C., times of about 10-24 hours are usually adequate. At C., the reaction appears complete in about 20-30 minutes with times of from 20 minutes to three hours being used; at C., 3 to 5 minutes are adequate. Generally, a slight molar excess of the acid halide is employed since it is the less expensive reactant. AMBAX/acid halide ratios of 1:1 to 1:2.0 are generally preferred with ratio of 1:1.1 to 1:1.3 being most preferred.

This AMBAX addition product is then cyclized with base. ##STR19##

The base employed is not critical, any strong inorganic base such as NaOH, KOH or the like will work. From 0.5 to 2 equivalents (basis colorant) of base may be used. This step is generally carried out at elevated temperatures such as C. to C. with temperatures of C. to C. being preferred. This step can immediately follow the acid halide addition step by adding base to the crude halide addition product and heating for from about five minutes to about 24 hours. At C. 24 hours is a good reaction time, at C., 15 minutes to one hour are employed. At C., five minutes are employed. Otherwise, the halide addition product can be isolated by evaporation of solvent and crystallization and dissolved in fresh inert aprotic solvent such as those used for the addition and then treated with base. This more complicated method offers some yield advantages. Both methods yield the new intermediate. ##STR20## wherein R.sub.1 and R.sub.2 are as already defined. It will be appreciated that the Br substituent is present principally because the AMBAX starting material is a bromo compound. Other halo leaving groups (i.e., Cl.sup.-, I.sup.-) are essentially equivalent. The examples which follow will show the preparation of such equivalent materials. This intermediate may be further reacted at this stage to introduce or change the R.sub.1 and R.sub.2 substituents. Particularly, sulfonate R.sub.1 's or R.sub.2 's may be introduced at this stage by liquid phase contact with 100% H.sub.2 SO.sub.4 at C. for 0.5 to 2 hours, or by treatment with 15-30% oleum at room temperature ( C.) to C. for 0.5 to 5 hours.

The intermediate is next coupled to an amine. This may be an amine group-containing polymer backbone as has been described. In this step the amine displaces the halo-leaving group on the anthraquinone ring as follows: ##STR21##

This step is carried out in liquid phase as well, generally in a water or mixed water/organic solvent and base and with a copper catalyst. This amine displacement is an adaption of the classic Ullmann reaction.

Water, and water containing up to about 25% of a water-miscible organic, such as an alkanol or glycol (methanol, ethanol, ethylene glycol and the like), mono and dialkyl ethers of ethylene glycols such as the materials marketed by Union Carbide under the trademark Cellosolve.RTM., and liquid organic bases such as pyridine may be used as solvent. Water and water containing up to about 20% pyridine are preferred solvents. The copper catalyst useful for this coupling may be copper metal, a copper (preferably cuprous) salt or an oxide of copper, for example finely divided copper metal, Cu.sub.2 Cl.sub.2, and Cu.sub.2 O supported on carbon black. A catalytically effective amount of catalyst is employed. Such an amount can range from about 0.01 to about 0.5 equivalents (preferably 0.05 to 0.4 equivalents) of copper per equivalent of reactive amine. Base, especially a strong inorganic base such as NaOH or KOH, should be present in an amount in excess of the molar amount of chromophore being coupled. Preferably from 0.5 to 5 equivalents (basis-free amine) of base is present with amounts from 1 to 3 (especially about 2) equivalents giving best results. The coupling is effected at a temperature of from about C. to about C., preferably C. to about C., and a time of from about 0.2 hours to about 24 hours, preferably 0.5 hours to about 8 hours, depending upon the temperature. This yields the coupled product ##STR22## as a crude reaction mixture. The desired product can be freed of catalyst and impurities as desired. It may also be subjected to post treatments such as acetylation or the like as desired.

The second preparative route is similar to the first. The acid chloride is attached to the AMBAX in the same way. Then, however, instead of separately cyclizing the AMBAX addition product, the uncyclized addition product is coupled to the amine or amine-containing backbone with the conditions of the coupling also effecting cyclization. Economies of production may favor the second route, but yields and product purities are often somewhat higher with the longer process.

A third preparative route is the new route disclosed by D. Keeley in United States patent application, Ser. No. 130,667, filed Mar. 17, 1980, wherein the chromophore intermediate is formed by the titanium/pyridine catalyzed condensation of a suitably substituted phenylacetic acid with the halo aminoanthraquinone. These products are excellent red colors. Those containing polar groups in their chromophores or attached to their amines (i.e., when the backbone contains a polar group) are water-soluble. As solutions, they present clear, bright, intense reds. When added in coloring amounts such as from 10 to 10,000 ppm wt, they bond to and dye fibers and other substrates.

As polymeric dyes they present especially advantageous utilities as colorants for edibles. The polymer compounds wherein R.sub.1 and R.sub.2 are hydrogen are especially useful in this application as these materials are virtually a direct match in hue for now-banned Red #2. The other polymeric members of this colorant family are good reds for foods, blending well with yellows and blues to give the range of oranges, reds and grapes desired by the food industry.

For food use the colorants generally have molecular weights above about 1000 Daltons, preferably above about 2000 Daltons so as to preclude their absorption through the walls of the G.I. tract.

In edible applications the polymeric colors are dissolved in beverages and syrups, dry mixed into powdered drink mix and cake mix, and otherwise conventionally admixed with foods, beverages, pharmaceuticals and cosmetics. The amount of color used in these applications will range between about 10 ppm wt and about 1000 ppm wt, basis finished food, beverage, or pharmaceutical. Cosmetic uses may require higher use levels.

The use of the present polymeric dyes in food systems is very straightforward because the polymeric dyes, especially those containing sulfonate groups in their structure behave very much like the monomeric red FD&C dyes they replace. Thus, the art-known methods of addition and incorporation may suitably be employed.

In addition to use as "straight" soluble colors, the present red polymeric dyes may be deposited alone or with other polymeric or monomeric dyes onto the surface of particulate inorganic oxidic substrates, carriers or extenders to form insoluble pigments. These pigments, which may also be thought of as lakes, constitute another aspect of the present invention. The particulate substrate, carrier or extender may be classified as an inorganic oxidic material. Such materials include aluminaceous solids such as alumina, e.g., high and low activity alumina hydrate or light alumina hydrate which may take the forms Al.sub.2 O.sub.3.SO.sub.3.3H.sub.2 O orr 5 Al.sub.2 O.sub.3.2SO.sub.3.xH.sub.2 O, gloss white [3 BaSO.sub.4.Al(OH).sub.3], talc, clay, silica, zinc oxide, baria, boria, titania, zirconia, magnesia, mixtures thereof, and the like. These materials are colorless or nearly so. These materials are most easily handled as pastes or suspensions and have particle sizes of from 0.5 to 50 microns generally with excellent results being achieved with particle sizes from 1 to 20 microns. Aluminaceous solids, especially the alumina hydrates, are the most commonly used substrates and are preferred in the present lakes.

The amount of colorant adsorbed onto the surface of the substrate particle may vary from as little as 1% to as much as 75%, basis total colorant plus substrate weight. The amounts of dye (also known as loadings) in the higher ranges, such as from 30% to 75%, are most unexpected as such loadings are not achieved with lakes of conventional monomeric dyes. Preferred loadings are from about 3% to about 50% with loadings of from about 5% to 35% being most preferred. These lakes have the advantages of being insoluble in acids and of not bleeding in use in the presence of salts or acids.

Lakes can be prepared by the general lake-forming reactions known in the art. One representative method is as follows.

(1) A weighed amount of alumina paste is slurried with approximately 3 to 4 times its weight of deionized water.

(2) The pH of the slurry (7.9-8.0) is adjusted to pH 4.2 by the dropwise addition of 1:1 HCl. A calculated amount of dye (based on the solids content of the alumina cake) is dissolved in the minimum amount of deionized water and then slowly added to the alumina slurry over a period of 15 to 20 minutes with constant, non-shear stirring (e.g., magnetic stirring bar or the like).

(3) During the addition of the dye and for approximately two hours thereafter, the pH of the slurry is maintained at about 4.2 with small additions of 1:10 HCl.

(4) The adsorption of dye onto the alumina is followed by spotting drops of the dispersion onto filter paper and observing bleed. Bleed is the spread of color which is due to the presence of soluble dye in the liquid phase of the dispersion. The reaction is considered terminated when bleed is not observed or when further reaction does not cause bleed to diminish.

(5) Finally, the lake is filtered through a funnel and washed thoroughly with small aliquots of deionized water. The filter cake is dried in an oven at F. to constant weight, and the resulting product ground in a mortar.

The lake products essentially are insoluble pigments and may be used in pigment applications. They may be used in inks, in paints, and in colorings for edible and nonedible substrates such as frostings, candies, plastics, gelatin products, medicaments, pills and the like. In such uses the lakes may be present in a color imparting concentration such as from 1 ppm to as much as 10,000 ppm wt, or preferably 10 to 1000 ppm wt basic total composition.

The invention is further illustrated by the following examples. These are intended solely to exemplify the invention and are not to be construed as limiting the scope of the invention which is instead defined solely by the appended claims.


Preparation of ##STR23## wherein R.sub.1 and R.sub.2 are hydrogen.

A. 1-amino-2-methylanthraquinone (300 g) is slurried with 1500 ml of HOAc in a 5-liter flask. The temperature is raised to C. Neat bromine (405 g) is added over 21/2 hours with stirring at C. The mixture is stirred for 20 additional minutes and filtered. The solids so recovered are washed with HOAc and water and sucked dry with an aspirator and transferred to a reaction flask along with 150 g of NaHSO.sub.3 and 1.5 liters of water. The mixture is gradually heated to C. (over two hours) with stirring to give 1-amino-2-methyl-4-bromoanthraquinone as a solid which is recovered from the reaction mixture by filtration in 90% yield, rinsed with water and dried overnight at C. and 1 mm Hg absolute vacuum.

It will be appreciated that chlorine or iodine could be substituted for bromine in this reaction if desired.

______________________________________ ##STR24## ##STR25## ______________________________________ Wt used 15.8 g 8.5 g 21.7 g (theory) Moles used 0.050 0.055 Ratio 1.0 1.1 ______________________________________

A 250 ml flask equipped with overhead stirrer, water-cooled condenser, and Ar inlet is charged with the bromoanthraquinone of part A and 120 ml of toluene. To the red slurry is added the phenylacetyl chloride and the mixture is heated to reflux. The reaction is followed by thin-layer chromatography. After one hour most of the starting material is gone. After three hours, the reaction appears to be over, although some starting material still remains.

After 3.5 hours total refluxing, the reaction is cooled to ca. and filtered. The dark yellow filtrate is concentrated to ca. 30 ml on a rotary evaporator and cooled. A large amount of dark solid forms which is isolated and washed with ether until a yellow (dark) solid is obtained. The solid is oven dried at, <1 mm, for four hours to afford 12.5 g (57.6%) of yellow-green solid product.

______________________________________ ##STR26## ##STR27## ______________________________________ Wt used 4.56 g 0.45 g 4.37 g (theory) Moles used 10.5 mmole 8.0 mg - f.w. ______________________________________

A 100 ml 3-necked flask is equipped with water-cooled condenser, overhead stirrer, thermowell, and Ar inlet. The flask is charged with the phenylacetyl product of Part B, and 30 ml methyl cellosolve. The contents are heated to and the KOH in 0.6 ml H.sub.2 O is added dropwise over one minute. The reaction is stirred at for one hour.

The reaction mixture is cooled to about C. Isolation of a solid precipitate, followed by washing, affords 1.71 g (39.1% of bright, shining gold solid.

The dark, yellow filtrate is concentrated via rotary evaporator to dryness and the dark solid is recrystallized from 170 ml of HOAc to afford 2.3 g (52.6%) of a dull, golden colored powder. Total yield is 4.01 g (91.8%).


To 2304 g of acetamide (technical) in a 12 liter reaction flask is added 62.2 ml of 6M aqueous sulfuric acid followed immediately by 661 g of acetaldehyde (99.sup.+ %). This mixture is stirred and heated until the internal temperature reaches C. (11 minutes) at which point the clear solution spontaneously crystallizes, causing a temperature rise to C. The reaction product, ethylidene-bis-acetamide, is not separated. Heating and stirring are continued for another five minutes to a temperature of C. and a mixture of 150 g calcium carbonate (precipitated chalk) and 150 g of Celite.RTM. diatomaceous earth powder is added. A first distillate fraction of water and acetamide is removed. The remaining materials are cracked at 35 mm Hg and C. A fraction made up of vinylacetamide and acetamide is taken overhead, analyzed by NMR and found to contain 720 g of vinylacetamide and 306 g of acetamide. A portion of this pooled material is dissolved in isopropanol, cooled, and filtered to yield a stock solution. This stock solution is analyzed and found to be 4.1 molar in vinylacetamide.

Into a five liter flask is added 505 ml (272 g) of a vinylacetamide solution obtained by stripping isopropanol from 900 ml of the above stock solution (containing 3.69 moles of vinylacetamide). AIBN (15 g) in 1500 ml of water is added followed by 1279 g of 25% W sodium vinylsulfonate in water (Research Organic Corporation) and a liter of water. This is two equivalents of sulfonate per three equivalents of vinylacetamide. Following deoxygenation, the mixture is heated to C. and there maintained with stirring for three hours. This reaction mixture is then reduced to 2/3 volume, solid AIBN is removed and the liquid added to eight gallons of isopropanol. The copolymer precipitate is collected and dried in vacuum to yield 865 g of solid copolymer (MW 6.6.times.10.sup.4). Whenever an experimental molecular weight is given in this specification, it is derived by gel permeation techniques. In the primary technique, a silanized porous glass support is used with a 0.01 M LiBr in DMF eluent. Detection is by refractometer with standardization being based on suitable purchased poly(styrene) or poly(styrene sulfonate) standards.

Into a two liter flask is added 863 g of the just-noted solid product, 2.5 liters of water and a liter of concentrated hydrochloric acid. The mixture is refluxed ( C.) for about 24 hours and cooled, the solid precipitate is washed, and dissolved in three liters of 10% NaOH. This mixture is added to about 12 liters of methanol to give 400 g of fine solid copolymer precipitate.


______________________________________ ##STR28## ##STR29## ______________________________________ Wt. used 0.985 g 0.500 g 0.077 g Moles used 2.30 mmol 3.835 meq 0.39 mg - f.w. Ratio 0.60 1.0 0.20 equiv. Cu.sup.+ ______________________________________

A 50 ml two-necked flask is charged with the copolymer, 11.5 ml 1 N NaOH, 1 ml of pyridine and 4 ml H.sub.2 O. The system is de-aerated. The polymer dissolves and the anthraquinone and Cu.sub.2 Cl.sub.2 are added and the mixture is heated to After 21/2 hr, the mixture is cooled and diluted with 40 ml water at pH 11.

The diluted mixture is filtered to afford 100 ml of a red solution. The solution is ultrafiltered using 10% pyridine in water at pH 11 and later pH 7 water as makeup.

The red solution is lyophilized to afford 0.850 g of red solid which is determined to be ##STR30##


Preparation of an acetylated version of the colorant of Example III.

The product of Example III (255 mg) is dissolved in 12 ml of water and cooled to C. Fifty percent NaOH is added to pH 12 followed by 0.2 g of acetic anhydride. The pH adjustment to 12 and acetic anhydride addition are repeated twice. The red solution is filtered, ultrafiltered and lyophilized to yield a solid product of Example IV wherein about 95% of the free backbone amines are converted to ##STR31## groups. This red solid is an excellent colorant. It is very good replacement for existing red food colors. Virtually identical colors would result when the following changes are made.

1. The backbone amine to sulfonate ratio is varied from 1.5:1 to 2.0:1.

2. The backbone peak molecular weight is varied from 35,000 to 80,000.

3. The fraction of total backbone amines substituted with chromophores is varied from 25% to 40%.

4. The degree of acetylation is varied between 80% to 98% of the total amines.


Preparation of

______________________________________ ##STR32## ##STR33## ______________________________________ Wt. used 17.06 g 11.90 g 18.9 g (theory) Moles used 0.100 0.100 ______________________________________

A 50 ml flask is charged with the organic acid and the SOCl.sub.2. A single boiling chip is added and the flask fitted with air condenser and drying tube. Heating in a oil bath is begun. The reaction is cooled after 23 hours.

To the solution is added 5 ml of benzene. Volatile material is pumped off at room temperature at 0.5 mm Hg. The product is then distilled through a short path vacuum distillation apparatus as a water white product, b.p. at 0.10 mm Hg. The yield of distilled product is 12.3 g (65%).

______________________________________ ##STR34## ##STR35## ______________________________________ Wt. used 15.8 g 10.87 g 120 ml 23.4 g (theory) Moles used 0.050 0.0575 Ratio 1.0 1.15 ______________________________________

The procedure of Example I, Part B, is repeated using the above materials to afford the above product.

______________________________________ ##STR36## ##STR37## ______________________________________ Wt. used 9.85 g 0.88 g 9.46 g (theory) Moles used 0.021 0.0157 g Ratio 1.0 0.75 ______________________________________

The product of Part B and 60 ml of Cellosolve are added to a 250 ml flask. The slurry is heated to The KOH is dissolved in 1.0 ml H.sub.2 O and added over one minute. The reaction is cooled after heating at for 35 minutes. The mixture is allowed to cool slowly to room temperature and then cooled to C. A solid precipitate is isolated and washed to afford 3.32 g of glittering, brownish/golden crystals.

The dark filtrate is concentrated to dryness and the resultant dark solid recrystallized from 675 ml boiling HOAc. The greenish-yellow needles are isolated and washed. Drying at, <1 mm for four hours affords 3.8 g of a golden solid.


If the preparation of Example V is repeated using the chloro or iodoanthraquinones shown in Example I in place of the bromoanthraquinone, the corresponding chloro or iodo products would result.

Similarly, use of the 2,4-dichloro, the 2-chloro, the bromo or the iodo equivalents of the 4-chloro acid in place of the 4-chloro acid in step A of Example VI would result in the 2,4-dichloro, the 2-chloro, the bromo or the iodo-substituted products.


Attachment of the product of Example V to the polymer of Example II.

______________________________________ ##STR38## ##STR39## ______________________________________ Wt. used 1.037 g 0.500 0.077 g Cu.sub.2 Cl.sub.2 Mmoles used 2.30 3.835 meq 0.39 mg of Cu.sub.2 Cl.sub.2 11.5 mmole OH.sup.- Ratio 0.6 1.0 0.2 equiv Cu.sup.+ 3.0 equiv. OH.sup.- ______________________________________

The copolymer is dissolved in 11.5 ml 1 N NaOH and 4 ml H.sub.2 O. The solution is de-aerated (3 times, with Ar) and the anthrapyridone derivative, Cu.sub.2 Cl.sub.2, and pyridine (1.5 ml) are added. The reaction is stirred at for two hours and 40 minutes, then cooled and diluted with dilute aqueous sodium hydroxide.

The dilute mixture is filtered to afford 115 ml of a dark red dye solution. Ultrafiltration is carried out with 10% pyridine pH 11 water. Then, the product is divided into two portions.

One portion is acetylated and the other is lyophilized to afford 490 mg of red solid in accord with Example IV.

The unacetylated product has the formula ##STR40## The acetylated version differs only in that the residual NH.sub.2 's on the backbone are present as NHAc's. Both are excellent red colorants.

Substitution of the products of Example VI for the product of Example V as feedstock for this Example would yield their polymer product counterparts.


Preparation of ##STR41##

The product of Example I, ##STR42## 0.6 g and 4.4 g of 20% oleum are stirred together at room temperature. After one-half hour, it appears that reaction has occurred. The stirring is continued for a total of five hours. The reaction mixture is poured over ice and water and a solid precipitate forms and is collected. The solid is dissolved in a liter of 2 M NH.sub.4 OH, filtered and the solution is evaporated to dryness. The solid which results is extracted with methanol. The methanol is evaporated to afford 0.775 g of the desired sulfonate product.


Formation of a homopolymeric polyaminoethylene backbone for coupling colors into polymeric form.

A red-brown solution of 460 g of vinylacetamide, 557 g acetamide, and 123 g ethylidene-bis-acetamide, (one-half of five combined vinylacetamide preparations essentially in accord with Example III) in 570 ml methanol is filtered through 250 g of Amberlite.RTM. IRC-50 ion exchange resin over an eight-hour period. The column is rinsed with 1000 ml methanol. The combined column eluent is stripped to its original volume of 1,667 ml, treated with 7.75 g of AIBN polymerization catalyst (1 mole %), deoxygenated, and stirred under Argon at C. for 15 hours to polymerize. Solid polymer is precipitated from the resulting very thick solution by addition to 15 liters of acetone. The polymer is collected by filtration, washed with acetone and dried in a vacuum oven ( C.) for two days to afford 459 g of crude poly(vinylacetamide) contaminated with acetamide as a yellow, semigranular solid having molecular weight of 2.times.10.sup.4 as determined by Gel Permeation Chromatography, using dimethylformamide as eluent and polystyrene as standards.

The crude poly(vinylacetamide) (459 g) is dissolved in 1000 ml water with heating. Concentrated hydrochloric acid (1000 ml) is added and the resulting dark brown solution is stirred and heated at a gentle reflux ( C.) for 19 hours. A precipitate forms and is redissolved by addition of 200 ml water. Reflux is continued and over the next eight hours 1000 ml water is added in several portions to maintain solubility of the polymer. After a total of 27 hours at reflux, the polymer is precipitated by the addition of 1000 ml concentrated hydrochloric acid. The mixture is cooled to C. and the thick polymeric gum isolated by decantation and dried under vacuum at C. with occasional pulverization for 40 hours to give 332 g of poly(vinylamine hydrochloride) as a brown granular solid (77% yield from vinylacetamide, 59% from acetaldehyde).


Formation of a polymeric colorant from the anthraquinone product of Example VIII and the polymer product of Example IV.

Following the procedures of Examples IV, 0.754 g of the anthraquinone product of Example VIII is coupled to 0.200 g of the polyaminoethylene product of Example IX. Copper catalyst (0.021 g) and NaOH (three equivalents basis polymer) are used. The reaction is carried out for one hour at C. The reaction mixture is diluted and filtered and ultrafiltered. The retentate of the ultrafiltration is divided into two portions. One is lyophilized to afford the following product ##STR43## The other portion is acetylated in accord with the general procedure of Example IV to give a product wherein the residual backbone amines are acetylated. In this and in all acetylations in this disclosure, conversion of amines to amides is usually not quantitative. Usual conversions are 80-98% of the amine being converted.



______________________________________ ##STR44##

______________________________________ Wt. Used 18.11 g 12.0 19.9 (theory) Moles Used 0.100 0.101 ______________________________________

The reagents are weighed into a flask and allowed to stand at room temperature ( overnight. A stirring bar is added and the reaction driven to completion by warming at until no solid is visible (five additional hours). To the red solution is added 5 mls benzene and the volatile material is removed with vacuum.

B. The 2-nitro acid chloride of Part A is reacted with AMBAX and the ring is closed to give the product ##STR45## The general reactions of Example I are used. The reaction of this acid chloride with AMBAX is more facile and requires only three hours at reflux.

C. The product of Part B is attached to the polymer of Example II using the method of Example IV. This product is divided into two portions, one of which is acetylated.



______________________________________ ##STR46##

______________________________________ Wt. Used 16.61 g 11.90 g 18.4 g (theory) Moles Used 0.100 0.100 ______________________________________

A flask is charged with the carboxylic acid and thionyl chloride and allowed to stand at room temperature with occasional swirling for 24 hours. The endothermic reaction begins immediately and proceeds at a very good rate, generating an orange solution.

After 24 hours, nearly all gas evolution has ceased. Six ml benzene is added and the volatile material is removed with vacuum. The product is purified by distillation.

B. A flask is charged with 15.8 g AMBAX and 115 ml toluene. Then, the acid chloride, 10:1 g, is added. The red slurry is heated to reflux for 2.0 hours.

The hot mixture is filtered and a black residue washed with three portions of hot toluene. The toluene is stripped off affording a solid which is washed with ether. The product is dried overnight at, <1 mm to afford 19.48 g of dull green powder.

This product is treated with base in accord with the procedures of Example I, Part C, to yield ##STR47##

C. The product of Part B is coupled to the polymer of Example II to afford a polymeric dye of the structure ##STR48##


This example illustrates an alternative preparation of the compound of this invention.

______________________________________ ##STR49## ##STR50## ##STR51## ______________________________________ Wt. used 1.897 kg 1.113 kg 370 g Moles used 6.0 7.2 Ratio 1.0 1.2 ______________________________________

A 22-liter resin kettle is charged with the anthraquinone and 13.8 liter of diglyme. The reactor is fitted with a 4-necked head which is equipped with overhead stirrer, thermocouple, argon outlet/reflux condenser, and an argon inlet to sweep the system. The reaction mixture is then heated to and the acid chloride is added quickly. After 30 minutes at, a pH probe is inserted into the reaction mixture in place of the argon inlet. A solution of 370 g of potassium hydroxide in 346 ml of water is then carefully added portionwise while the pH of the system is monitored. By the end of the hydroxide addition, the pH meter should give a reading of ca. 10.3. Product soon begins to drop out and after a total reaction time of 90 minutes (including 30 minute acetylation time) the heating mantle is turned off.

Next the system is cooled refluxively by gradually reducing the internal pressure using a water aspirator. When the pressure reaches 27-inch Hg of vacuum, the internal temperature is The vacuum is released and 3 liter of methanol are added. The resultant slurry is then filtered via a ceramic filtering crock and sucked dry. The filter cake is washed with one 4-liter portion of methanol, sucked dry at a large water aspirator, and finally vacuum oven dried overnight at, 0.4 mm Hg. The yield of yellow-green product is 1.904 kg (76%).


This example shows a one-step closing and attachment to a backbone.

______________________________________ ##STR52## ##STR53## ______________________________________ Wt. Used 1.0 g 2.4 g 0.076 g Moles Used 2.3 mmole 3.84 meq 0.39 mmole Cu.sub.2 Cl.sub.2 Ratio 0.6 1.0 0.20 eq. Cu.sup.+ ______________________________________

A 25 ml flask is charged with the anthraquinone derivative, the copolymer backbone, 11.5 mls 1 N NaOH solution, 1.3 mls pyridine, and the cuprous chloride. The flask is equipped with reflux condenser, magnetic stirrer, and thermocouple. The system is then de-aerated and flushed with argon. The reaction mixture next is stirred and heated at C. for 3.5 hours, after which time the reaction mixture is cooled, diluted, filtered, and ultrafiltered. The resultant dye is then acetylated as in Example IV and worked up as in Example III to afford a red dye which is indistinguishable from the dye prepared according to Example IV.


In the preceding Examples, all salts are sodium salts, since the bases used in their preparation are sodium bases. It will be appreciated that by substituting corresponding potassium bases in the preparations, potassium salts could be formed. Similarly, ammonium cations, or other pharmaceutically acceptable cations, can be substituted in the products.


A lake is prepared from the polymeric red colorant of Example IV. Aluminum hydroxide, wet gel (44.8 g), is dispersed in 225 ml distilled water with a magnetic stirrer. This amount of wet gel, by analysis, is shown to contain 8.0 g of Al.sub.2 O.sub.3 and 36.8 g of water. Hydrochloric acid 1:1 concentration is dripped in until the solution pH is 4.0 by pH electrode measurement. The colorant of Example IV, 2.0018 g, is dissolved in 200 ml of distilled water. The solution of colorant is gradually added to the rapidly stirring suspension of aluminum hydroxide. The pH is held at 4.2-4.3. The polymeric colorant is adsorbed onto the surface of the aluminum hydroxide. Initially, only part of the dye is adsorbed such that a drop of the suspension on filter paper causes a deposit of colored solid (lake) at the center and a colored "halo" of dissolved colorant. After stirring for about an hour, the colorant is completely exhausted onto the alumina and the "halo" is colorless. The lake product is calculated to contain 20% (basis total weight of lake) of color. The lake is recovered by filtration, washed and spread to dry in pans in an oven at C. When dry, the lakes are lumpy and agglomerated. Grinding produces the desired pigment-like powder. This lake is a bright red. It has the advantageous properties of being insoluble in acid and of not bleeding in acid.


The lake preparation of Example XVII is repeated four times varying the amount of colorant solution employed. In the first repeat, 400 ml of solution is used, thus yielding a final product containing 33% w colorant and having a darker red shade than the lake of Example XVI. In the second repeat, 600 ml of solution is used, yielding a yet darker red product containing 43% colorant. In the third repeat, 100 ml of solution is used, yielding a lighter red lake containing 11% colorant. In the last repeat, 50 ml of colorant is used, yielding a pinkish red 5.5% w colorant lake.


The lake preparation of Example XVI is repeated with one change. Instead of the colorant of Example I, a mixture of 1.5 g of the colorant of Example IV and 0.5 g of a polymeric yellow colorant of the formula ##STR54## prepared by the method of Dawson et al, U.S. Ser. No. 948,465, is employed. This results in a bright red-orange lake product which has the same advantageous properties observed with the lake of Example XVI.


The lake preparation of Example XVI is repeated three times, each time varying the inorganic oxidic substrate. First, finely divided titania, (titanium dioxide) is used. Second, finely divided zirconia is used. Finally, silica is used. In each case, a lake is formed which is similar in character to the lake of Example XVI.


Colorants prepared in the preceding Examples may be employed as colors for edible materials.

A. A "cherry" soft drink beverage powder is prepared.

The color of Example IV, 25 g, is dissolved in deionized water to form a red colored solution. Next, 81 kg of dry granulated sugar (sucrose), 200-100 mesh, is tumbled in a ribbon blender. The color solution is then sprayed onto the surface of the tumbling sugar particles over 1-3 minutes. The tumbling is continued for another 1-3 minutes to uniformly color the sugar particles. Then, a very finely ground powdered dessicant, anhydrous calcium phosphate, may be added to the tumbling sugar to dry the yellow color onto the surface of the sugar particles. No more than about 500 g of dessicant is required. Alternatively, C. dry air may be blown through the blender for a few minutes to dry the sugar particles. The mixture is a free flowing powder. Then, two minutes after phosphate addition, the following components are added to the mixer as 20-100 mesh dry powders.

3 kg of dried gum arabic clouding agent,

5 kg of citric acid,

5 kg of citric acid,

0.5 kg of ascorbic acid,

1 kg of sodium citrate,

1.5 kg of a Cherry Extract Formula comprising ethyl acetate, ethyl butyrate, benzaldehyde and ethyl ornanthate.

This combination is tumbled for an additional ten minutes and packaged in water vapor impermeable envelopes. When 80 grams of this product are added to 950 ml of water, a red colored "cherry" soft drink noncarbonated beverage is obtained.

B. The preparation of A. is repeated with two changes. In place of the 25 g of the color of Example I a mixture of 20 g of that color with 10 g of monomeric Tartrazine (FD&C Yellow #5) is employed in the first repeat. An orange oil solidified emulsion in corn syrup is substituted for the cherry extract. This blend of red of this invention with an FD&C dye results in a mixture which, upon addition to water, yields an orangeade style beverage.

C. The preparation of B. is repeated with one change; in place of 10 g of Yellow #5, 15 g of a polymeric yellow dye of the formula ##STR55## prepared in accord with the teachings of U.S. Ser. No. 948,465 of Dawson et al is employed. This blend of a red of this invention with another polymeric dye yields a very suitable orange colored beverage mix which, upon addition to water, produces an orangeade style beverage.

D. The colors of this invention find use in dietetic foods and beverages where their nonabsorbability properties present the bonus of imparting a noncaloric property to the colors as well. A dietetic orange beverage concentrate is prepared. First, a colored bulking agent is formed by dissolving 10 kg of corn syrup solids, 100 g of sodium saccharin, 3 g of the red of Example IV and 30 g of the polymeric yellow used in preparation C. in water and spray-drying. This yields a dry solid. This solid (6.5 kg) is charged to a laboratory scale V blender and tumbled. The yellow and red colors are firmly fixed into the bulking agent and do not segregate. The following other materials are added and tumbled.

______________________________________ Citric Acid 1300 g Clouding agent - hydrogenated vegetable oil 500 g Sodium carboxymethylcellulose 500 g Ascorbic Acid 200 g Sodium Citrate 200 g Orange Flavor, including Firmenich Imit. Orange Flavor 59,427/AP Perma Stable Orange Flavors 6007 and 6032 Fries and Fries Art. Orange Flavors 11736 and 11169 750 g ______________________________________

These materials dry-blend into the bulking agent. When this blended product is dissolved in water at a concentration of about 4%, it yields a noncarbonated dietary orange beverage. When it is dissolved in carbonic acid-saturated water at a level of 3.0%, an orange-colored carbonated drink results.

E. The colors are used in baked on coating mixes. First, a concentrated solution of 2 parts of the color of Example V and 20 parts of FD&C yellow #5 is prepared and gradually added to 200 parts of granulated sugar tumbling in a blender. Warm ( C.) dry air is passed through the tumbling mass to remove water and form a dry colored sugar powder. This powder is used in the following coating mix.

______________________________________ Component Percent by Weight ______________________________________ Flour 15 Bread crumbs 57.75 Salt 7 Monosodium glutamate 1 Herbs and spices 1 Solid fat powder 15 Calcium phosphate 3 Color powder 0.25 ______________________________________

This mixture (150 g) is placed in a plastic bag. Uncooked chicken pieces, previously dipped in milk, are added to the bag, shaken with the coating mix, removed, placed in a single layer on a cookie sheet and baked for 50 minutes at F. The coating mix employing the color of this invention imparts a uniform golden "simulated deep fried" color to the chicken as it bakes.

F. The red color of this invention prepared in Example IV is dissolved in distilled water at a 2% level. This solution is packaged for use as a food coloring for frostings, cakes, decorated eggs and other home uses.

G. Using the methods of spraying a solution of color onto sugar grains shown in preparation A., a color of Example X is added to sugar which, in turn, is used as a component in a powder for making strawberry flavored gelatin desserts.

H. The polymeric colorant of Example IX is used to color gelatin capsules for medicaments. USP gelatin is dissolved in water with heating. The colorant of Example VII, 300 ppm (basis weight of gelatin) is added. The colored gelatin solution is then formed into red capsules by methods known to the art.

I. The polymeric lake of Example XVI is employed in a pill coating. USP gelatin is dissolved in water and evaporated to give a solution the consistency of light cream. The lake of Example XVI, 200 ppm basis weight of gelatin, is then suspended in the gelatin solution. Ascorbic acid tablets and aspirin tablets are covered with this yellow suspension and quickly dried to obtain red coated tablets.

J. The polymeric lake of Example XVII is used as a component of cosmetics. It is blended and ground with yellow lakes and brown lakes. Ten parts of this blend of lake are then added to a melt composed of 15 parts beeswax, 4 parts petrolatum, 55 parts semihydrogenated castor oil, 10 parts paraffin oil, and 4 parts lanolin. This mixture is stirred and compounded on a heated roller mill and placed in containers. It serves as an anhydrous cream rouge.

K. The polymeric lake of the third preparation of Example XVI is employed as a coloring in frosting. Margarine (500 g) is placed in a mixer, followed by 0.5 g of the lake of preparation 3 of Example X as a fine (100% passes 300 mesh) powder. The lake is thoroughly blended into the margarine. Then, B 4 kg of confectioners sugar, 30 ml of imitation vanilla extract, and 30 g of salt are added to the mixture and slowly blended with the margarine. Water is gradually added until a spreadable coherent mass of red colored frosting is obtained.

L. The polymeric colorant of Example X is used as a colorant for a detergent based shampoo.

______________________________________ Fatty acid-protein condensation products 30% Triethanolamine lauryl sulfate 20% Sodium alginate (3% solution) 5% Glycerol 3% Water 42% Color of Example VIII 100 ppm ______________________________________

are combined in a blender and mixed until homogeneous. This yields a red-colored shampoo product employing the colorant of this invention.


1. A colored edible comprising an edible substrate in intimate admixture with a color-imparting concentration of from 10 to 1000 ppm by weight basis edible substrate of a water-soluble polymeric red colorant having the formula ##STR56## wherein R.sub.1 and R.sub.2 are independently selected from the group of hydrogen, halos of atomic number 9 through 53 inclusive, lower alkyls and lower alkoxies of from 1 to 3 carbon atoms, nitro, and sulfonate; R.sub.3 is hydrogen or a lower alkyl of 1 to 3 carbon atoms, B is an organic polymeric backbone attached to N by a covalent bond and characterized as having essentially no crosslinks and as being selected from among linear polyethyleneoxy backbones and linear polyalkylene backbones each having a molecular weight of from about 10,000 to about 150,000 Daltons, and n is a number from 10 to 4000.

2. The colored edible of claim 1 wherein the edible substrate is food.

3. The colored edible of claim 1 wherein the edible substrate is a beverage.

4. The colored edible of claim 1 wherein the edible substrate is a drug.

5. The colored edible of claim 1 wherein the edible substrate is a cosmetic.

6. The colored edible of claim 1 wherein B is a linear polyalkylene carbon-carbon backbone having a molecular weight of from about 10,000 to about 150,000 daltons and n is a number from 10 to 4000.

7. A colored edible comprising an edible substrate having admixed therewith from 10 ppm wt to 1000 ppm wt, basis edible substrate, of the polymeric colorant having the formula: ##STR57## wherein R.sub.1, R.sub.2 and R.sub.3 are each hydrogen; R.sub.6 is acetyl; M is an alkali metal selected from sodium and potassium; n, m and p are numbers wherein n is from 10 to 2000, m is from 0.3 to 5 times n, and p is 0.3 to 2 times the sum of n+m.

8. The colored edible of claim 7 wherein the edible substrate is a food.

9. The colored edible of claim 7 wherein the edible substrate is a beverage.

10. The colored edible of claim 9 wherein the beverage is a carbonated beverage.

11. The colored edible of claim 9 wherein the beverage is a noncarbonated beverage.

12. A colored edible material comprising an edible material in intimate admixture with a color imparting concentration of from about 1 to about 10,000 ppm of the acid-insoluble pigment comprising a particulate inorganic oxidic substrate having deposited on the surface thereof a polymeric colorant in an amount of from 1 to 75%, basis weight of total pigment, said colorant having the formula ##STR58## wherein R.sub.1 and R.sub.2 are independently selected from the group of hydrogen, halos of atomic number 9 through 53 inclusive, lower alkyls and lower alkoxies of from 1 to 3 carbon atoms, nitro, and sulfonate; R.sub.3 is hydrogen or a lower alkyl of 1 to 3 carbon atoms, B is an organic polymeric backbone attached to N by a covalent bond and characterized as having essentially no crosslinks and containing only covalent bonds stable under the acidic, basic and enzymatic conditions of the mammalian gastrointestinal tract; and n is a number from 10 to 4000.

13. The colored edible material of claim 12 wherein said edible material is a food.

14. The colored edible material of claim 12 wherein the edible is a food and the color-imparting amount is in the range of from 10 to 1000 ppm weight, basis total edible plus pigment.

Referenced Cited
U.S. Patent Documents
3920855 November 1975 Dawson et al.
3937851 February 10, 1976 Bellanca et al.
3940503 February 24, 1976 Bellanca
3976797 August 24, 1976 Furia
4167422 September 11, 1979 Bellanca et al.
4182885 January 8, 1980 Bunes
4196294 April 1, 1980 Bunes
4233328 November 11, 1980 Dawson et al.
4258189 March 24, 1981 Wang et al.
Foreign Patent Documents
658114 March 1938 DE2
827961 February 1938 FRX
964602 July 1964 GBX
965235 July 1964 GBX
Patent History
Patent number: 4316918
Type: Grant
Filed: Jun 24, 1980
Date of Patent: Feb 23, 1982
Assignee: Dynapol (Palo Alto, CA)
Inventor: Leonard A. Bunes (San Carlos, CA)
Primary Examiner: Jeanette M. Hunter
Attorneys: William H. Benz, Thomas E. Ciotti, Norman H. Stepno
Application Number: 6/162,456